Candidate: James M. O'Brien, Jr., MD is committed to becoming an independent researcher in critical care health services research with interests in patient-oriented outcomes and processes of care. His background includes a strong foundation in academic medicine, excellent training in pulmonary and critical care medicine, and scholarly work applicable to his future research plans. His talents combine a passion for providing high quality care to ICU patients with a driving interest to study the processes of provided care and to expand the repertoire of outcome measures used to evaluate critically ill patients. The K23 career development award will provide the time and support required for him to continue his training and advance his research objectives. Environment: The mentorship and institutional resources available to Dr. O'Brien create a unique environment for the nurturing of a career in a relatively novel field: critical care health services research. Andrew Kramer, MD (sponsor) and Carolyn Welsh, MD (co-sponsor) bring the complementary talents of expertise in health service research and clinical critical care research, respectively, to provide the candidate with support that crosses traditional boundaries of patient-oriented research. The candidate's appointment is through the Division of Pulmonary Science and Critical Care Medicine at the University of Colorado Health Sciences Center although he will continue to benefit from the resources of the Division of Health Care Policy and Research. Research: The global ambition of the proposed studies is to better understand the role of excess body weight as a risk factor for worse outcomes from critical illness and for substandard ICU care (as determined by process measures). A prospective, observational, cohort study will explore the influence of obesity on (1) short-term clinical outcomes (number of ventilator-free days); (2) resource utilization (ICU length of stay); (3) long-term survival; and (4) patient-oriented outcome measures (health-related quality of life). In this study, we will also attend to process measures (duration of "weaning" from mechanical ventilation and TISS-28 scores) as a surrogate for the quality of care. These studies will describe the effect of excess body weight on critical illness and produce a new type of independent investigator - the ICU health services researcher.